Exploring Multiple Aspects of Taxonomic and Functional Diversity in Microphytobenthic Communities: Effects of Environmental Gradients and Temporal Changes

Abstract

Biodiversity has traditionally been quantified using taxonomic information but the importance of also considering its functional characteristics has recently gained an increasing attention among microorganisms. However, studies exploring multiple aspects of taxonomic and functional diversity and their temporal variations are scarce for diatoms, which is one of the most important microbial groups in aquatic ecosystems. Here, our aim was to examine the taxonomic and functional alpha and beta diversities of diatoms in a coastal rock pool system characterized by a naturally high environmental heterogeneity. We also investigated the temporal differences in the diversity patterns and drivers. The relationship between the species richness and functional dispersion was temporally coherent, such that species-poor communities tended to be functionally clustered. The trend between the species richness and taxonomic uniqueness of community composition was temporally inconsistent, changing from negative to non-significant over time. Conductivity or distance to the sea or both were key determinants of species richness, functional dispersion, and uniqueness of community composition. The increase of community dissimilarity with an increasing environmental distance was stronger for the taxonomic than the functional composition. Our results suggest that even minor decreases in the species richness may result in a lowered functional diversity and decreased ecosystem functioning. Species-poor ecosystems may, however, have unique species compositions and high contributions to regional biodiversity. Despite changing the species compositions along the environmental gradients, communities may remain to have a high functional similarity and robustness in the face of environmental changes. Our results highlight the advantage of considering multiple biodiversity metrics and incorporating a temporal component for a deeper understanding of the effects of environmental changes on microbial biodiversity.

Vegetation Height as the Primary Driver of Functional Changes in Orthopteran Assemblages in a Roadside Habitat

“…Trait-based approaches link community and ecosystem functions to environmental change through functional traits, i.e., phenotypic traits that define the interactions between species and their environment, influencing performance or fitness [ 13 , 15 ]. A simplified, function-based community structure thus obtained [ 16 ] can be used to quantify functional diversity, as a measure of the value and range of functional traits within a given assemblage [ 17 , 18 ]. This enables comparisons among different ecosystems, providing valuable insights into the patterns and processes affecting assemblages, regardless of their taxonomic composition [ 17 ].…”

“…A simplified, function-based community structure thus obtained [ 16 ] can be used to quantify functional diversity, as a measure of the value and range of functional traits within a given assemblage [ 17 , 18 ]. This enables comparisons among different ecosystems, providing valuable insights into the patterns and processes affecting assemblages, regardless of their taxonomic composition [ 17 ]. Despite the obvious merits of this approach in studying, e.g., the ecology of roadside plant communities [ 19 , 20 ], few studies have attempted to relate road-associated disturbance to functional changes in insect assemblages so far [ 21 ].…”

Distance decay 2.0 – A global synthesis of taxonomic and functional turnover in ecological communities

“…Regarding environmental gradients, functional distance decay was also weaker than taxonomic distance decay. Although counterintuitive, this relationship has been found previously (Heino & Tolonen, 2017;da Silva & Hernández, 2015;Teittinen & Virta, 2021).…”

Studying biodiversity–ecosystem function relationships in experimental microcosms among islands

“…Noteworthy, the diatom species richness in the microcosms was lower than the richness of the sea samples collected from the littoral of each island and the richness of diatom communities observed in natural rock pools on these islands (Teittinen & Virta, 2021 ). The lower richness may be explained using several ways of reasoning.…”

“…We also measured the distances to 10 closest rock pools and calculated their mean to represent the distance to rock pools on each island. Rock pools among these islands provide small aquatic habitats, which harbor diatom communities along a freshwater to brackish transition (Teittinen & Virta, 2021 ) and may therefore serve as diatom source pools for the microcosms.…”